Domain forwarding and authority sites

Hey there,
I found a great untouched niche yesterday and bought three TLD's. Creating a blog for every domain would be senseless since the content is the same. Now the question is how is google treating domain forwarding?

For example, the blog is optimized for three keywords (A,B,C) and is installed on Domain A. Domain B and C are forwarding to the blog on A, how would Google rank them? Would they crawl an empty page or the content of Domain A?

I know it sounds a bit confusing but I don't know how I could describe it better

How do you mean forwarded, like a 301 redirect?

This question has been asked so many times...

The answer is 301 two of the domains to the main domain.